Pollutant Concentrations

Air quality readings will be available hourly from 7am to 11pm. Air quality readings from 12am to 6am will be made available at 7am on the same day.

Readings on 20 Nov 2014

View reading for:

Region

24-hr Sulphur dioxide(µg/m3)

24-hr PM10(µg/m3)

1-hr Nitrogen dioxide(µg/m3)a

8-hr Ozone(µg/m3)

8-hr Carbon monoxide(mg/m3)

24-hr PM2.5(µg/m3)

North

5(3)

19(19)

36(-)

18(8)

0.3(3)

10(42)

South

8(5)

21(21)

38(-)

15(6)

0.4(4)

11(46)

East

6(4)

18(18)

10(-)

24(10)

0.3(3)

12(49)

West

5(3)

21(21)

32(-)

27(12)

0.4(4)

10(42)

Central

7(4)

17(17)

40(-)

27(11)

0.5(5)

10(40)

1-hr PM2.5 (µg/m3)b Readings on 19 Nov 2014

View reading for:

Time

1am

2am

3am

4am

5am

6am

7am

8am

9am

10am

11am

12pm

North

22

21

16

14

9

5

7

9

10

2

8

11

South

10

13

10

5

6

8

9

6

11

8

10

13

East

15

25

19

21

19

14

7

16

15

15

12

17

West

9

8

15

6

7

10

7

6

2

6

8

11

Central

18

10

13

8

10

9

13

8

9

7

5

10

Time

1pm

2pm

3pm

4pm

5pm

6pm

7pm

8pm

9pm

10pm

11pm

12am

North

10

13

13

13

8

6

7

8

6

8

9

5

South

16

19

15

28

22

11

8

10

6

8

9

2

East

5

5

9

15

12

3

10

6

5

6

6

4

West

12

12

14

17

30

14

7

9

8

8

8

6

Central

15

7

13

23

7

7

8

9

8

6

6

2

Note:a Sub-index for nitrogen dioxide is reported only when the 1-hr concentration equals or exceeds 1130 µg/m3.

b There is no sub-index for 1-hr PM2.5.

3-hr PSI Readings from 1am to 12am on
19 Nov 2014

Time

1am

2am

3am

4am

5am

6am

7am

8am

9am

10am

11am

12pm

3-hr PSI

52

53

54

52

49

42

39

37

37

36

36

39

Time

1pm

2pm

3pm

4pm

5pm

6pm

7pm

8pm

9pm

10pm

11pm

12am

3-hr PSI

45

49

50

54

55

54

44

34

32

31

30

27

Hourly updates of 3-hr PSI readings are provided from 7am to 11pm. The 3-hr PSI readings from 12am to 6am will be made available at 7am on the same day. The 3-hr PSI readings are calculated based on PM2.5 concentrations only.